Acute respiratory distress syndrome, ARDS, is of multifactorial etiology and afflicts 50,000 to 90,000 Americans each year and 18% of all ventilated patients. Despite sophisticated intensive care, the mortality rate ranges between 15 and 72% with a mean of 43%. Patients with ARDS have impaired surfactant function and continued inflammation-induced metabolism of surfactant indicating that a single treatment with surfactant is inadequate. The delivery of pulmonary surfactant to treat lung diseases such as ARDS and RDS has been via the instillation of 20 to 80 mg/ml of suspensions of surfactant at doses generally ranging from 100 mg to 200 mg/kg. Multiple bolus intrapulmonary instillations of surfactant are traumatic for the patient and physician alike and lead to undesirable peri- and post- treatment events. Aerosolized surfactant may require a considerably lower dose to achieve a similar physiological effect. It also eliminates the hypercapnia seen on bolus instillation. In neonates aerosolized surfactant has been delivered over 3 hour treatment periods. This situation is markedly exacerbated when attempting to deliver the same dose/kg of aerosolized surfactant to adults. SUPRAER uses a single-pass low shear nozzle to generate an ~10 m diameter aqueous aerosol. This aerosol plume is arrested by a counter-flow gas stream and rapidly dried by warm compressed gas and dilution gas as well as infrared radiation. The resulting fine particle aerosol is concentrated using a low resistance virtual impactor and delivered at the output on demand. Two classes of single-pass, low shear aerosol generation nozzles that aerosolize 100% of the surfactant will be evaluated. We will optimize the heat and mass transfer of the evaporation process as well as the other components of the aerosol processing system to provide aerosols containing a high mass loading of surfactant that can be predicted to deposit in the alveolar regions of the lungs. Our target is to demonstrate that clinically relevant doses of surfactant aerosols can be generated and delivered in 50-100 minutes. The delivery of surfactant in a gentler, non-invasive manner would empower the clinician to provide improved life support and potentially a marked improvement in survival. This important new technological innovation will also be applicable to treat other diseases of the lungs that require drugs whose efficacy depends on high doses being delivered in a short time. Short treatment times lead to better patient adherence, efficacy and improved health care.